In a large bowl, mix together 6 tablespoons salted butter (room temperature), 3 tablespoons tamarind chutney, 2 tablespoons garam masala and ¼ teaspoon each kosher salt and ground black pepper. Prepare, grill and husk the corn as directed. Add the husked ears a few at a time to the bowl with the butter mixture and turn to coat. Return the corn to the hot side of the grill and cook, uncovered and turning occasionally, until lightly charred on all sides, 5 to 7 minutes; move the ears to the cool side if flare-ups become too intense. Transfer the ears to a platter, then sprinkle with ⅓ cup unsweetened shredded coconut (toasted) and ⅓ cup lightly packed fresh cilantro (chopped).